Effects of High-Energy Electron Beam-Modified Fumed Silica on the Structure and Properties of Silicone Rubber Composites

This study investigates the effects of high-energy electron beam irradiation on fumed silica fillers and the subsequent impact on the properties of synthesized silicone rubber. A systematic examination of the physical and electrical properties of the modified fumed silica and silicone rubber materials is conducted, and the underlying mechanisms behind the irradiated fumed silica's influence on the silicone rubber are analyzed using first principles calculations. The findings reveal that as the irradiation dose increases, more defect structures emerge, and the defect center transitions from a dimer configuration to a puckered configuration. First principles calculations confirm that this defect center alteration leads to reduced surface energy. Fumed silica containing a higher number of defect structures results in improved mechanical properties and decreased dielectric properties for the silicone rubber material. These outcomes primarily stem from the increased presence of oxygen vacancies in the irradiated fumed silica, which correlates with reduced surface energy and energy band gap in the first principles calculations. This research is essential for understanding the microscopic changes in fumed silica as a filler under irradiation and the mechanism of its effect on silicone rubber, ultimately providing guidance for enhancing the functionality of silicone rubber materials.